For manganese oxidation in surface water, which pH value would be sufficient to make the process effective?

For manganese oxidation in surface water, which pH value would be sufficient to make the process effective?

• A. 9.0
• B. 9.2
• C. 9.5
• D. 9.8

Answer: (C)

Manganese removal by oxidation relies on pH; as the water becomes more alkaline, Mn2+ is more readily oxidized and forms insoluble MnO2 that can be filtered out. The higher the pH, the faster and more complete that oxidation and precipitation proceed. Among the given pH values, around 9.5 is the point where oxidation becomes reliably effective. At lower values like 9.0 or 9.2, the reaction is slower and may not yield enough MnO2 for easy removal. A pH of 9.5 provides the necessary conditions for efficient manganese oxidation and precipitation, making it the best choice among the options. Higher pH, such as 9.8, would also work, but 9.5 is the minimum threshold indicated here.

Manganese removal by oxidation relies on pH; as the water becomes more alkaline, Mn2+ is more readily oxidized and forms insoluble MnO2 that can be filtered out. The higher the pH, the faster and more complete that oxidation and precipitation proceed.

Among the given pH values, around 9.5 is the point where oxidation becomes reliably effective. At lower values like 9.0 or 9.2, the reaction is slower and may not yield enough MnO2 for easy removal. A pH of 9.5 provides the necessary conditions for efficient manganese oxidation and precipitation, making it the best choice among the options. Higher pH, such as 9.8, would also work, but 9.5 is the minimum threshold indicated here.